The Korean War, 1950–53


The Korean War was the first major armed clash between Free World and Communist forces, as the so-called Cold War turned hot.

From a pamphlet by John J. McGrath of U.S. Army Center of Military History,

written to honour Korean War veterans (2003).


The Korean War was the time when the Cold War became a global conflict.

In 1945, Korea was freed from the Japanese.   US troops stayed in Korea until 1946.   The country was split in half at the 38th parallel:

  • North Korea (led by Kim Il Sung) was Communist.

  • South Korea (led by Syngman Rhee) was capitalist.

The two countries hated each other.


What caused it? [DUCKS]

1.   President Truman was interested in the Far East:

  • Domino theory:  
    Europe was not the only place where Communists were coming to power.  In the Far East, too, they were getting powerful – China turned Communist in 1949.  Truman believed that, if one country fell to Communism, then others would follow, like a line of dominoes.  He was worried that, if Korea fell, the Communists would capture Japan.  

Domino Theory

Source A

This map from an American magazine published 14th November 1950 shows how much they feared the spread of Communism in the far east.

Click on the map for a larger version.


  • Undermine Communism:
    In April 1950, the American National Security Council issued a report (NSC 68) recommending that America abandon 'containment' and start 'rolling back' Communism.

  • Cold War:
    Truman realised the USA was in a competition for world dmination with the USSR.  By supporting South Korea, Aerica was able to fight Communism without directly attacking Russia.


2.   Stalin, also, was involved in the Far East:

  • Kim Il Sung visited Stalin
    In 1949, he persuaded Stalin that he could conquer South Korea.  Stalin did not think that America would dare to get involved, so he gave his agreement.  Stalin saw a chance to continue the cold war and discomfort America, but ‘at arm’s length’ – without directly confronting the Americans.  Kim Il Sung also went to see Mao Zedong, the leader of China, to get his agreement.


3.   Syngman Rhee

In 1950, Syngman Rhee boasted that he was going to attack North Korea.  It was a good enough excuse – the North Koreans invaded South Korea.


This started the Korean War.


New Words

global: whole world.

38th parallel: wanting to build an empire (communists used it as an abuse-word about the western powers).

Kim Il Sung

Syngman Rhee

Mao Zedong: leader of China (sometimes spelled Mao Tse Tung)




- Giles Hill on the Korean War


   Why did the Korean War break out in 1950?

   Describe the main events of the Korean War, 1950–53



Did you know

Korea was split at the 38th parallel because, when they were discussing what to do with Korea, the Americans could only find a small-scale map.





























Source B

Asia is where the communist conspirators have decided to make their play for global conquest.  If we lose this war, the fall of Europe is inevitable.  There is no choice but victory.

US General MacArthur, speaking in 1950.





1.   Study Source A.  Why was Korea so important for the Americans?

2.   Take each of the causes of the Korean War, and explain how it caused the war.


Source C

This cartoon by the British cartoonist David Low, from the Daily Herald (30 Jun 1950), shows Truman and the United Nations rushing to Korea’s aid.

Click here for the interpretation

Did you know?

The TV series M*A*S*H was set in the Korean War.   Because it was written at the time of the Vietnam War, the programmes had a strong anti-war message.



The Events of the War, 1950–53


    The war had FIVE phases:



Korean War web sites:

BBC site


  Film clip


Account by a North Korean  (detailed, but really instructive)

No Gun Ri - a BBC investigation of a US atrocity

Long list of more links (



June - Sept 1950

On 25 June 1950, the North Koreans attacked.  They were very successful.  The North Korean People's Army (NKPA) easily defeated the Republic of Korea's army (the ROKs)  

They captured most of South Korea.


The Americans were alarmed (see Source A).

On 27 June they persuaded the United Nations to pass a resolution supporting South Korea. 


The Americans sent troops to Korea to reinforce the South Korean Army at Pusan.  




Sept - Nov 1950

On 15 September, the American General MacArthur led a UN amphibious landing at Inchon (near Seoul) behind the NKPA .  Out of the 300,000 UN troops, 260,000 were Americans.


In danger of being cut off, the NKPA had to retreat.   The Americans drove them back and recaptured South Korea.   125,000 NKPA prisoners were taken.


On 7 October 1950 MacArthur invaded North Korea.  He advanced as far as the Chinese border.  He boasted that the Americans would be 'home by Christmas'.



Nov 1950 - Feb 1951  

Now the Chinese were alarmed.


On 25 November, 200,000 Chinese troops ('People's Volunteers') attacked MacArthur.  They had modern weapons supplied by Russia, and a fanatical hatred of the Americans.  


Then, on 31 December, half a million more Chinese troops entered the war and attacked the Americans.  They drove the Americans back (using 'human wave tactics').  They recaptured North Korea, and advanced into South Korea.


February – March 1951  

The Americans landed more troops.  They used bombers. 


The Chinese admitted to losing 150,000 men dead - western sources put the figure at nearly a million Chinese and half a million North Koreans dead.  The Americans drove the Chinese back, but admitted losing 35,000 American soldiers dead doing so (the Chinese claimed they lost 390,000).


MacArthur reached the 38th parallel in March 1951.


March 1951 – 1953

Truman told MacArthur to stop.   MacArthur was sacked when he publicly criticised Truman’s order.  


In 1953, Eisenhower became American president.   The Americans threatened to use the atomic bomb if China did not stop fighting.  


The Chinese agree to a truce, which was signed on 27 July 1953. 


Wikipedia puts the full battle death toll on all sides at just over 1.2 million, but many civilians also died in the war, with estimates varying from 2 to 4 million